BoilerFaultCodesYour boiler has stopped working because the water pressure is too low for the system to run safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Insufficient water pressure in the system (less than 0.5 bar)
What causes this fault?
This fault occurs when the water level inside your central heating system drops too low for the boiler to operate safely. The most common reasons are a slow leak from a radiator valve or pipework, or the air being manually bled from radiators without the pressure being topped back up.
This code is particularly common in autumn when homeowners first turn their heating back on after summer, causing old seals to weep or revealing pressures that have slowly dropped during months of inactivity.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two taps/levers on the filling loop to allow water into the system.Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close the taps fully.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F0 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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